Organic electroluminescent compound and organic electroluminescent device comprising the same

ABSTRACT

The present disclosure relates to an organic electroluminescent compound and an organic electroluminescent device comprising the same. The organic electroluminescent compound of the present disclosure may be comprised in a light-emitting layer, and is effective for producing an organic electroluminescent device having high luminescent efficiency and/or excellent lifespan characteristic.

TECHNICAL FIELD

The present disclosure relates to an organic electroluminescent compoundand an organic electroluminescent device comprising the same.

BACKGROUND ART

An electroluminescent (EL) device is a self-light-emitting device whichhas advantages in that it provides a wider viewing angle, a greatercontrast ratio, and a faster response time. An organic EL device wasfirst developed by Eastman Kodak in 1987, by using small aromaticdiamine molecules and aluminum complexes as materials for forming alight-emitting layer [Appl. Phys. Lett. 51, 913, 1987].

An organic electroluminescent device (OLED) changes electric energy intolight by applying electricity to an organic light-emitting material, andcommonly comprises an anode, a cathode, and an organic layer formedbetween the two electrodes. The organic layer of the OLED may comprise ahole injection layer, a hole transport layer, a hole auxiliary layer, alight-emitting auxiliary layer, an electron blocking layer, alight-emitting layer (containing host and dopant materials), an electronbuffer layer, a hole blocking layer, an electron transport layer, anelectron injection layer, etc. The materials used in the organic layercan be classified into a hole injection material, a hole transportmaterial, a hole auxiliary material, a light-emitting auxiliarymaterial, an electron blocking material, a light-emitting material, anelectron buffer material, a hole blocking material, an electrontransport material, an electron injection material, etc., depending onfunctions. In the OLED, due to an application of a voltage, holes areinjected from the anode to the light-emitting layer, electrons areinjected from the cathode to the light-emitting layer, and excitons ofhigh energies are formed by a recombination of the holes and theelectrons. By this energy, organic luminescent compounds reach anexcited state, and light emission occurs by emitting light from energydue to the excited state of the organic luminescent compounds returningto a ground state.

Recently, according to larger area of displays, light-emitting materialswhich can exhibit more delicate and vivid colors are required.Specifically, in the case of blue light-emitting materials, materialssuch as ADN and DPVBi are used as a host material, and materials such asaromatic amine-based compounds, copper phthalocyanine compounds,carbazole-based derivatives, perylene-based derivatives, coumarin-basedderivatives, and pyrene-based derivatives are used as a dopant material.However, these materials are difficult to obtain a deep blue color withhigh color purity, and are problematic due to having shorterlight-emitting lifespan as the wavelength gets shorter.

Accordingly, in realizing a full color display, developments oflight-emitting materials of deep blue having long lifespan and otherorganic materials having a suitable energy level with the bluelight-emitting material are required.

U.S. Pat. No. 8,759,818 and U.S. Patent Application Publication No.2014/0001459 disclose an organic electroluminescent compound comprisingan anthracene moiety in which some hydrogen atoms are substituted withdeuterium. However, these references do not specifically disclose anorganic electroluminescent compound comprising an anthracene moiety inwhich some hydrogen atoms are substituted with deuterium, and wherein adibenzofuran is substituted in a certain position.

DISCLOSURE OF INVENTION Technical Problems

The objective of the present disclosure is firstly. to provide anorganic electroluminescent compound effective for producing an organicelectroluminescent device having excellent lifespan characteristic, andsecondly, to provide an organic electroluminescent device comprising theorganic electroluminescent compound.

Solution to Problem

In an organic electroluminescent device, an improvement of a bluelight-emitting material or blue light-emitting device is important.However, from the beginning of the time when organic electroluminescentdevice was developed, there was no change in using a compound having amain moiety of anthracene as a blue host material. Thus, there was alimit in improving lifespan characteristics of a blue light-emittingmaterial or blue light-emitting device. In order to improve the lifespancharacteristic, the stability of an anthracene compound comprised in theblue host material can be increased. One of the methods is deuteration.When deuterating an anthracene compound, the zero point vibration energyof the compound can be lowered, thereby increasing the bond dissociationenergy (BDE) of the compound. Thus, the stability of the anthracenecompound can be increased. FIG. 1 is a graph showing the increase of thebond dissociation energy due to deuteration. Specifically, the presentinventors found that when deuterating the organic electroluminescentcompound having a specific structure of the following formula 1, a morenoticeable improvement in lifespan results compared to anthracenecompounds having other structures. By bonding a heteroaryl instead of anaryl to an anthracene core, the mobilities of holes and/or electrons canbe improved, thereby decreasing the driving voltage.

wherein

R₁ to R₈ each independently represent hydrogen, deuterium, a halogen, acyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted orunsubstituted (C6-C30)aryl, or a substituted or unsubstituted (5- to0-membered)heteroaryl, with a proviso that one of R₂ to R₄ is bonded to

R₉ to R₁₈ each independently represent hydrogen or deuterium;

Ar₁ represents a substituted or unsubstituted (C6-C30)aryl, or asubstituted or unsubstituted (5- to 30-membered)heteroaryl;

D_(N) means that N hydrogen atoms are substituted with deuterium; and

N represents an integer of 8 to 50.

Advantageous Effects of Invention

By using the organic electroluminescent compound according to thepresent disclosure, it is possible to produce an organicelectroluminescent device having improved blue light-emitting lifespan.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph illustrating an increase of the bond dissociationenergy due to deuteration.

MODE FOR THE INVENTION

Hereinafter, the present disclosure will be described in detail.However, the following description is intended to explain the invention,and is not meant in any way to restrict the scope of the invention.

The term “organic electroluminescent compound” in the present disclosuremeans a compound that may be used in an organic electroluminescentdevice, and may be comprised in any layer constituting an organicelectroluminescent device, as necessary.

The term “organic electroluminescent material” in the present disclosuremeans a material that may be used in an organic electroluminescentdevice, and may comprise at least one compound. The organicelectroluminescent material may be comprised in any layer constitutingan organic electroluminescent device, as necessary. For example, theorganic electroluminescent material may be a hole injection material, ahole transport material, a hole auxiliary material, a light-emittingauxiliary material, an electron blocking material, a light-emittingmaterial, an electron buffer material, a hole blocking material, anelectron transport material, an electron injection material, etc.

The organic electroluminescent material of the present disclosure maycomprise at least one compound represented by formula 1. The compoundrepresented by formula 1 may be comprised in a light-emitting layer or ahole transport layer, but is not limited thereto. For example, whencomprised in a light-emitting layer, the compound represented by formula1 may be comprised as a host such as a host for blue light-emission.According to one embodiment of the present disclosure, the compound offormula 1 may be a fluorescent host, for example, a fluorescent host forblue light-emission.

Hereinafter, the compound represented by formula 1 will be described inmore detail.

Herein, the term “(C1-C30)alkyl” is meant to be a linear or branchedalkyl having 1 to 30 carbon atoms constituting the chain, in which thenumber of carbon atoms is preferably 1 to 20, and more preferably 1 to10. The above alkyl may include methyl, ethyl, n-propyl, iso-propyl,n-butyl, iso-butyl, tert-butyl, etc. The term “(C2-C30)alkenyl” is meantto be a linear or branched alkenyl having 2 to 30 carbon atomsconstituting the chain, in which the number of carbon atoms ispreferably 2 to 20, and more preferably 2 to 10. The above alkenyl mayinclude vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl,2-methylbut-2-enyl, etc. The term “(C2-C30)alkynyl” is meant to be alinear or branched alkynyl having 2 to 30 carbon atoms constituting thechain, in which the number of carbon atoms is preferably 2 to 20, andmore preferably 2 to 10. The above alkynyl may include ethynyl,1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl,1-methylpent-2-ynyl, etc. The term “(C3-C30)cycloalkyl” is meant to be amono- or polycyclic hydrocarbon having 3 to 30 ring backbone carbonatoms, in which the number of carbon atoms is preferably 3 to 20, andmore preferably 3 to 7. The above cycloalkyl may include cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, etc. The term “(3- to7-membered)heterocycloalkyl” is meant to be a cycloalkyl having 3 to 7,preferably 5 to 7, ring backbone atoms, and including at least oneheteroatom selected from the group consisting of B, N, O, S, Si, and P,and preferably the group consisting of O. S, and N. The aboveheterocycloalkyl may include tetrahydrofuran, pyrrolidine, thiolan,tetrahydropyran, etc. The term “(C6-C30)aryl” is meant to be amonocyclic or fused ring radical derived from an aromatic hydrocarbonhaving 6 to 30 ring backbone carbon atoms, in which the number of thering backbone carbon atoms is preferably 6 to 25, more preferably 6 to18. The above aryl may be partially saturated, and may comprise a spirostructure. The above aryl may include phenyl, biphenyl, terphenyl,naphthyl, binaphthyl, phenyinaphthyl, naphthylphenyl, phenylterphenyl,fluorenyl, phenylfluorenyl, benzofluorenyl, dibenzofluorenyl,phenanthrenyl, phenylphenanthrenyl, anthracenyl, indenyl, triphenylenyl,pyrenyl, tetracenyl, perylenyl, chrysenyl, naphthacenyl, fluoranthenyl,spirobifluorenyl, azulenyl, etc. More specifically, the aryl may includephenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl,benzanthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl,9-phenanthryl, naphthacenyl, pyrenyl, 1-chrysenyl, 2-chrysenyl,3-chrysenyl, 4-chrysenyl, 5-chrysenyl, 6-chrysenyl, benzo[c]phenanthryl,benzo[g]chrysenyl, 1-triphenylenyl, 2-triphenylenyl, 3-triphenylenyl,4-triphenylenyl, 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl,9-fluorenyl, benzofluorenyl, dibenzofluorenyl, 2-biphenylyl,3-biphenylyl, 4-biphenylyl, o-terphenyl, m-terphenyl-4-yl,m-terphenyl-3-yl, m-terphenyl-2-yl, p-terphenyl-4-yl, p-terphenyl-3-yl,p-terphenyl-2-yl, m-quaterphenyl, 3-fluoranthenyl, 4-fluoranthenyl,8-fluoranthenyl, 9-fluoranthenyl, benzofluoranthenyl, o-tolyl, m-tolyl,p-tolyl, 2,3-xylyl, 3,4-xylyl, 2,5-xylyl, mesityl, o-cumenyl, m-cumenyl,p-cumenyl, p-t-butylphenyl, p-(2-phenylpropyl)phenyl,4′-methylbiphenylyl, 4″-t-butyl-p-terphenyl-4-yl,9,9-dimethyl-1-fluorenyl, 9,9-dimethyl-2-fluorenyl,9,9-dimethyl-3-fluorenyl, 9,9-dimethyl-4-fluorenyl, a9,9-diphenyl-1-fluorenyl, 9,9-diphenyl-2-fluorenyl,9,9-diphenyl-3-fluorenyl, 9,9-diphenyl-4-fluorenyl, etc.

Herein, the term “(3- to 30-membered)heteroaryl” is an aryl group having3 to 30 ring backbone atoms, and including at least one, preferably 1 to4 heteroatoms selected from the group consisting of B, N, O, S, Si, andP. The above heteroaryl may be a monocyclic ring, or a fused ringcondensed with at least one benzene ring; may be partially saturated;may be one formed by linking at least one heteroaryl or aryl group to aheteroaryl group via a single bond(s); and may comprise a spirostructure. The above heteroaryl may include a monocyclic ring-typeheteroaryl such as furyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl,thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl,oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl,pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, etc., and a fusedring-type heteroaryl such as benzofuranyl, benzothiophenyl,isobenzofuranyl, dibenzofuranyl, dibenzothiophenyl, benzonaphthofuranyl,benzonaphthothiophenyl, benzimidazolyl, benzothiazolyl,naphthothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl,isoindolyl, indolyl, benzoindolyl, indazolyl, benzothiadiazolyl,quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, benzoquinazolinyl,quinoxalinyl, benzoquinoxalinyl, naphthyridinyl, carbazolyl,benzocarbazolyl, dibenzocarbazolyl, phenoxazinyl, phenothiazinyl,phenanthridinyl, benzodioxolyl, dihydroacridinyl, etc. Morespecifically, the heteroaryl may include 1-pyrrolyl, 2-pyrrolyl,3-pyrrolyl, pyrazinyl, 2-pyridinyl, 2-pyrimidinyl, 4-pyrimidinyl,5-pyrimidinyl, 6-pyrimidinyl, 1,2,3-triazin-4-yl, 1,2,4-triazin-3-yl,1,3,5-triazin-2-yl, 1-imidazolyl, 2-imidazolyl, 1-pyrazolyl,1-indolidinyl, 2-indolidinyl, 3-indolidinyl, 5-indolidinyl,6-indolidinyl, 7-indolidinyl, 8-indolidinyl, 2-imidazopyridinyl,3-imidazopyridinyl, 5-imidazopyridinyl, 6-imidazopyridinyl,7-imidazopyridinyl, 8-imidazopyridinyl, 3-pyridinyl, 4-pyridinyl,1-indolyl, 2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl, 6-indolyl,7-indolyl, 1-isoindolyl, 2-isoindolyl, 3-isoindolyl, 4-isoindolyl,5-isoindolyl, 6-isoindolyl, 7-isoindolyl, 2-furyl, 3-furyl,2-benzofuranyl, 3-benzofuranyl, 4-benzofuranyl, 5-benzofuranyl,6-benzofuranyl, 7-benzofuranyl, 1-isobenzofuranyl, 3-isobenzofuranyl,4-isobenzofuranyl, 5-isobenzofuranyl, 6-isobenzofuranyl,7-isobenzofuranyl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl,6-quinolyl, 7-quinolyl, 8-quinolyl, 1-isoquinolyl, 3-isoquinolyl,4-isoquinolyl, 5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl,8-isoquinolyl, 2-quinoxalinyl, 5-quinoxalinyl, 6-quinoxalinyl,1-carbazolyl, 2-carbazolyl, 3-carbazolyl, 4-carbazolyl, 9-carbazolyl,azacarbazolyl-1-yl, azacarbazolyl-2-yl, azacarbazolyl-3-yl,azacarbazolyl-4-yl, azacarbazolyl-5-yl, azacarbazolyl-6-yl,azacarbazolyl-7-yl, azacarbazolyl-8-yl, azacarbazolyl-9-yl,1-phenanthridinyl, 2-phenanthridinyl, 3-phenanthridinyl,4-phenanthridinyl, 6-phenanthridinyl, 7-phenanthridinyl,8-phenanthridinyl, 9-phenanthridinyl, a 10-phenanthridinyl, 1-acridinyl,2-acridinyl, 3-acridinyl, 4-acridinyl, 9-acridinyl, 2-oxazolyl,4-oxazolyl, 5-oxazolyl, 2-oxadiazolyl, 5-oxadiazolyl, 3-furazanyl,2-thienyl, 3-thienyl, 2-methylpyrrol-1-yl, 2-methylpyrrol-3-yl,2-methylpyrrol-4-yl, 2-methylpyrrol-5-yl, 3-methylpyrrol-1-yl,3-methylpyrrol-2-yl, 3-methylpyrrol-4-yl, 3-methylpyrrol-5-yl,2-t-butylpyrrol-4-yl, 3-(2-phenylpropyl)pyrrol-1-yl, 2-methyl-1-indolyl,4-methyl-1-indolyl, 2-methyl-3-indolyl, 4-methyl-3-indolyl,2-t-butyl-1-indolyl, 4-t-butyl-1-indolyl, 2-t-butyl-3-indolyl,4-t-butyl-3-indolyl, 1-dibenzofuranyl, 2-dibenzofuranyl,3-dibenzofuranyl, 4-dibenzofuranyl, 1-dibenzothiophenyl,2-dibenzothiophenyl, 3-dibenzothiophenyl, 4-dibenzothiophenyl,1-silafluorenyl, 2-silafluorenyl, 3-silafluorenyl, 4-silafluorenyl,1-germafluorenyl, 2-germafluorenyl, 3-germafluorenyl, 4-germafluorenyl,etc. ‘Halogen’ includes F, Cl, Br, and I.

In addition. “ortho (o-),” “meta (m-).” and “para (p-)” are prefixes,which represent the relative positions of substituents, respectively.Ortho indicates that two substituents are adjacent to each other, andfor example, when two substituents in a benzene derivative occupypositions 1 and 2, it is called an ortho position. Meta indicates thattwo substituents are at positions 1 and 3, and for example, when twosubstituents in a benzene derivative occupy positions 1 and 3, it iscalled a meta position. Para indicates that two substituents are atpositions 1 and 4, and for example, when two substituents in a benzenederivative occupy positions 1 and 4, it is called a para position.

Herein, “substituted” in the expression “substituted or unsubstituted”means that a hydrogen atom in a certain functional group is replacedwith another atom or another functional group, i.e., a substituent. Thesubstituents of the substituted alkyl, the substituted aryl, and thesubstituted heteroaryl in R, to Re, and Ar₁ each independently are atleast one selected from the group consisting of deuterium; a halogen; acyano; a carboxyl; a nitro; a hydroxyl; a (C1-C30)alkyl; ahalo(C1-C30)alkyl; a (C2-C30)alkenyl; a (C2-C30)alkynyl; a(C1-C30)alkoxy; a (C1-C30)alkylthio; a (C3-C30)cycloalkyl; a(C3-C30)cycloalkenyl; a (3- to 7-membered)heterocycloalkyl; a(C6-C30)aryloxy; a (C6-C30)arylthio; a (3- to 30-membered)heteroarylunsubstituted or substituted with a (C6-C30)aryl(s); a (C6-C30)arylunsubstituted or substituted with at least one of a (C1-C30)alkyl(s) anda (3- to 30-membered)heteroaryl(s); a tri(C1-C30)alkylsilyl; atri(C6-C30)arylsilyl; a di(C1-C30)alkyl(C6-C30)arylsilyl; a(C1-C30)alkyldi(C6-C30)arylsilyl; an amino; a mono- ordi-(C1-C30)alkylamino; a mono- or di-(C6-C30)arylamino; a(C1-C30)alkyl(C6-C30)arylamino; a (C1-C30)alkylcarbonyl; a(C1-C30)alkoxycarbonyl; a (C6-C30)arylcarbonyl; a di(C6-C30)arylboronyl;a di(C1-C30)alkylboronyl; a (C1-C30)alkyl(C6-C30)arylboronyl; a(C6-C30)aryl(C1-C30)alkyl; and a (C1-C30)alkyl(C6-C30)aryl. According toone embodiment of the present disclosure, the substituents eachindependently are at least one selected from the group consisting of a(C1-C6)alkyl, a (C6-C15)aryl, and a (5- to 15-membered)heteroaryl.Specifically, the substituents each independently may be at least oneselected from the group consisting of a methyl, a phenyl, a naphthyl, abiphenyl, and a carbazolyl.

The compound represented by formula 1 may be represented by any one ofthe following formulas 1-1 to 1-3:

wherein

R₁ to R₈, R₉ to R₁₆, Ar₁, and D_(N) are as defined in formula 1, and

N represents an integer of 8 to 30.

In formula 1, R₁ to Re each independently represent hydrogen, deuterium,a halogen, a cyano, a substituted or unsubstituted (C1-C30)alkyl, asubstituted or unsubstituted (C6-C30)aryl, or a substituted orunsubstituted (5- to 30-membered)heteroaryl, with a proviso that one ofR₂ to R₄ is bonded to

In one embodiment of the present disclosure, one of R₂ to R₄ is bondedto

and the others of R₂ to R₄, R₁, and R₅ to R₈ each independentlyrepresent hydrogen or deuterium.

In formula 1, Ar₁ represents a substituted or unsubstituted(C6-C30)aryl, or a substituted or unsubstituted (5- to30-membered)heteroaryl. In one embodiment of the present disclosure. Ar₁represents a substituted or unsubstituted (C6-C25)aryl, or a substitutedor unsubstituted (5- to 20-membered)heteroaryl. In another embodiment ofthe present disclosure, Ar₁ represents a (C6-C25)aryl unsubstituted orsubstituted with at least one of a (C1-C6)alkyl(s), a (C6-C15)aryl(s),and a (5- to 15-membered)heteroaryl(s); or a (5- to20-membered)heteroaryl unsubstituted or substituted with a(C6-C12)aryl(s). Specifically, Ar₁ may represent a phenyl, a naphthyl, abiphenyl, a terphenyl, a phenanthrenyl, a naphthylphenyl, aphenyinaphthyl, a binaphthyl, a biphenylnaphthyl, a dimethylfluorenyl, adimethylbenzofluorenyl, a carbazolylphenyl, a carbazolyinaphthyl, aphenylbenzothiazolyl, a phenylbenzooxazolyl, a dibenzothiophenyl, aphenylcarbazolyl, a phenylnaphthothiazolyl, a benzonaphthofuranyl, aphenylbenzocarbazolyl, a 19-membered nitrogen-containing heteroaryl,etc.

In formula 1, D_(N) means that N hydrogen atoms in formula 1 aresubstituted with deuterium. N represents an integer of 8 to 50,preferably an integer of 8 to 40, more preferably an integer of 8 to 30,and even more preferably an integer of 13 to 30. When deuterated in thenumber of the lower limit or higher, the increase of the bonddissociation energy according to deuteration is sufficient to provide anoticeable increase in lifespan characteristics. The upper limit isdetermined according to the number of hydrogen atoms which can besubstituted in each compound.

In one embodiment of the present disclosure, in formula 1, R₁ to R₈which are not bonded to

each independently represent hydrogen or deuterium; and Ar₁ represents asubstituted or unsubstituted (C6-C25)aryl, or a substituted orunsubstituted (5- to 20-membered)heteroaryl.

In another embodiment of the present disclosure, in formula 1, R₁ to R₈which are not bonded to

each independently represent hydrogen or deuterium; and Ar₁ represents a(C6-C25)aryl unsubstituted or substituted with at least one of a(C1-C6)alkyl(s), a (C6-C15)aryl(s), and a (5- to15-membered)heteroaryl(s); or a (5- to 20-membered)heteroarylunsubstituted or substituted with a (C6-C12)aryl(s).

In the formulas of the present disclosure, if adjacent substituents arelinked to each other to form a ring, the ring may be a substituted orunsubstituted mono- or polycyclic (3- to 30-membered) alicyclic oraromatic ring, or the combination thereof, in which the formed ring maycontain at least one heteroatom selected from B, N, O, S, Si, and Rpreferably N, O, and S. According to one embodiment of the presentdisclosure, the number of the ring backbone atoms may be 5 to 20.According to another embodiment of the present disclosure, the number ofthe ring backbone atoms may be 5 to 15. For example, the fused ring maybe a substituted or unsubstituted dibenzothiophene ring, a substitutedor unsubstituted dibenzofuran ring, a substituted or unsubstitutednaphthalene ring, a substituted or unsubstituted phenanthrene ring, asubstituted or unsubstituted fluorene ring, a substituted orunsubstituted benzothiophene ring, a substituted or unsubstitutedbenzofuran ring, a substituted or unsubstituted indole ring, asubstituted or unsubstituted indene ring, a substituted or unsubstitutedbenzene ring, or a substituted or unsubstituted carbazole ring.

In the formulas of the present disclosure, the heteroaryl, eachindependently, may contain at least one heteroatom selected from B, N,O, S, Si, and P. In addition, the heteroatom may be bonded to at leastone selected from the group consisting of hydrogen, deuterium, ahalogen, a cyano, a substituted or unsubstituted (C1-C30)alkyl, asubstituted or unsubstituted (C6-C30)aryl, a substituted orunsubstituted (5- to 30-membered)heteroaryl, a substituted orunsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted(C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, asubstituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, asubstituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, asubstituted or unsubstituted tri(C6-C30)arylsilyl, a substituted orunsubstituted mono- or di-(C1-C30)alkylamino, a substituted orunsubstituted mono- or di-(C6-C30)arylamino, and a substituted orunsubstituted (C1-C30)alkyl(C6-C30)arylamino.

The compound represented by formula 1 includes the following compounds,but is not limited thereto.

The compound of formula 1 according to the present disclosure may beprepared by a synthetic method known to one skilled in the art, and forexample, as shown in the following reaction schemes but is not limitedthereto.

In reaction schemes 1 to 3, Ar₁, R₁ to R₈, R₉ to R₁₆, and D_(N) are asdefined in formula 1, and Hal represents a halogen.

In addition, the non-deuterated derivative of the compound representedby formula 1 may be prepared by a known coupling or substitutionreaction. The deuterated derivative may be prepared by a similar methodusing a deuterated precursor material, or more generally, treating anon-deuterated compound with a deuterated solvent, D6-benzene, etc., inthe presence of a Lewis acid such as aluminum trichloride or ethylaluminum chloride, a H/D exchange catalyst such astrifluoromethanesulfonic acid or trifluoromethanesulfonic acid-D, etc.Further, the degree of deuteration may be controlled by varying reactionconditions such as reaction temperature. For example, by controllingreaction temperature and time, acid equivalent, etc., the number of N informula 1 may be controlled.

Although illustrative synthesis examples of the compound represented byformula 1 were described above, one skilled in the art will be able toreadily understand that all of them are based on a Buchwald-Hartwigcross-coupling reaction, an N-arylation reaction, a H-mont-mediatedetherification reaction, a Miyaura borylation reaction, a Suzukicross-coupling reaction, an Intramolecular acid-induced cyclizationreaction, a Pd(II)-catalyzed oxidative cyclization reaction, a Grignardreaction, a Heck reaction, a Cyclic Dehydration reaction, an SN₁substitution reaction, an SN₂ substitution reaction, aPhosphine-mediated reductive cyclization reaction, etc., and the abovereactions proceed even when substituents, which are defined in formula 1above but are not specified in the specific synthesis examples, arebonded.

The present disclosure provides an organic electroluminescent materialcomprising the organic electroluminescent compound represented byformula 1, and an organic electroluminescent device comprising theorganic electroluminescent material. The material may consist of theorganic electroluminescent compound according to the present disclosurealone, or may further comprise conventional materials included in theorganic electroluminescent material.

The organic electroluminescent device according to the presentdisclosure comprises a first electrode, a second electrode, and at leastone organic layer between the first and second electrodes, in which theorganic layer may comprise at least one organic electroluminescentcompound represented by formula 1.

One of the first and second electrodes may be an anode, and the othermay be a cathode. The organic layer may comprise a light-emitting layer,and may further comprise at least one layer selected from a holeinjection layer, a hole transport layer, a hole auxiliary layer, alight-emitting auxiliary layer, an electron transport layer, an electronbuffer layer, an electron injection layer, an interlayer, a holeblocking layer, and an electron blocking layer.

The second electrode may be a a transflective electrode or a reflectiveelectrode, and the organic electroluminescent device may be a topemission type, a bottom emission type, or both-sides emission typeaccording to the kinds of the material formed.

The first electrode and the second electrode may each be formed with atransmissive conductive material, a transflective conductive material,or a reflective conductive material. The organic electroluminescentdevice may be a top emission type, a bottom emission type, or both-sidesemission type according to the kinds of the material forming the firstelectrode and the second electrode. In addition, the hole injectionlayer may be further doped with a p-dopant, and the electron injectionlayer may be further doped with an n-dopant.

The organic electroluminescent compound represented by formula 1 of thepresent disclosure may be comprised in at least one of a light-emittinglayer, a hole injection layer, a hole transport layer, a hole auxiliarylayer, a light-emitting auxiliary layer, an electron transport layer, anelectron buffer layer, an electron injection layer, an interlayer, ahole blocking layer, and an electron blocking layer, preferably, may becomprised in a light-emitting layer. When used in the light-emittinglayer, the organic electroluminescent compound represented by formula 1of the present disclosure may be comprised as a host material.Preferably, the light-emitting layer may further comprise at least onedopant. If necessary, the organic electroluminescent compound of thepresent disclosure may be used as a co-host material. That is, thelight-emitting layer may further include a compound other than theorganic electroluminescent compound represented by formula 1 of thepresent disclosure (first host material) as a second host material. Theweight ratio between the first host material and the second hostmaterial is in the range of 1:99 to 99:1.

The dopant comprised in the organic electroluminescent device of thepresent disclosure is at least one phosphorescent or fluorescent dopant,preferably at least one fluorescent dopant. The fluorescent dopantmaterial applied to the organic electroluminescent device of the presentdisclosure is not particulary limited.

The organic layer may further comprise at least one compound selectedfrom the group consisting of arylamine-based compounds andstyrylarylamine-based compounds.

In addition, in the organic electroluminescent device of the presentdisclosure, the organic layer may further comprise at least one metalselected from the group consisting of metals of Group 1, metals of Group2, transition metals of the 4^(th) period, transition metals of the5^(th) period, lanthanides and organic metals of d-transition elementsof the Periodic Table, or at least one complex compound comprising saidmetal.

The organic electroluminescent device of the present disclosure may emitwhite light by further including at least one light-emitting layercontaining a blue, red, or green light-emitting compound, which is knownin the art, besides the organic electroluminescent compound of thepresent disclosure. In addition, it may further include a yellow ororange light-emitting layer, if necessary.

In the organic electroluminescent device of the present disclosure, atleast one layer selected from a chalcogenide layer, a metal halide layerand a metal oxide layer (hereinafter, “a surface layer”) may bepreferably placed on an inner surface(s) of one or both electrodes.Specifically, a chalcogenide (including oxides) layer of silicon oraluminum is preferably placed on an anode surface of anelectroluminescent medium layer, and a metal halide layer or a metaloxide layer is preferably placed on a cathode surface of anelectroluminescent medium layer. The surface layer may provide operationstability for the organic electroluminescent device. Preferably, thechalcogenide includes SiO_(X) (1≤X≤2), AlO_(X) (1≤X≤1.5), SiON, SiAlON,etc.: the metal halide includes LiF, MgF₂, CaF₂, a rare earth metalfluoride, etc.; and the metal oxide includes Cs₂O, Li₂O, MgO, SrO, BaO,CaO, etc.

A hole injection layer, a hole transport layer, or an electron blockinglayer, or a combination thereof may be used between the anode and thelight-emitting layer. The hole injection layer may be multilayers inorder to lower the hole injection barrier (or hole injection voltage)from the anode to the hole transport layer or the electron blockinglayer, wherein each of the multilayers may use two compoundssimultaneously. The hole transport layer or the electron blocking layermay also be multilayers.

An electron buffer layer, a hole blocking layer, an electron transportlayer, or an electron injection layer, or a combination thereof can beused between the light-emitting layer and the cathode. The electronbuffer layer may be multilayers in order to control the injection of theelectron and improve the interfacial properties between thelight-emitting layer and the electron injection layer, wherein each ofthe multilayers may use two compounds simultaneously. The hole blockinglayer or the electron transport layer may also be multilayers, whereineach of the multilayers may use a plurality of compounds.

The light-emitting auxiliary layer may be placed between the anode andthe light-emitting layer, or between the cathode and the light-emittinglayer. When the light-emitting auxiliary layer is placed between theanode and the light-emitting layer, it can be used for promoting thehole injection and/or the hole transport, or for preventing the overflowof electrons. When the light-emitting auxiliary layer is placed betweenthe cathode and the light-emitting layer, it can be used for promotingthe electron injection and/or the electron transport, or for preventingthe overflow of holes. In addition, the hole auxiliary layer may beplaced between the hole transport layer (or hole injection layer) andthe light-emitting layer, and may be effective to promote or block thehole transport rate (or the hole injection rate), thereby enabling thecharge balance to be controlled. Further, the electron blocking layermay be placed between the hole transport layer (or hole injection layer)and the light-emitting layer, and may block overflowing electrons fromthe light-emitting layer and confine the excitons in the light-emittinglayer to prevent light leakage. When an organic electroluminescentdevice includes two or more hole transport layers, the hole transportlayer, which is further included, may be used as a hole auxiliary layeror an electron blocking layer. The hole auxiliary layer and the electronblocking layer may have an effect of improving the efficiency and/or thelifespan of the organic electroluminescent device.

In the organic electroluminescent device of the present disclosure, amixed region of an electron transport compound and a reductive dopant,or a mixed region of a hole transport compound and an oxidative dopantis preferably placed on at least one surface of a pair of electrodes. Inthis case, the electron transport compound is reduced to an anion, andthus it becomes easier to inject and transport electrons from the mixedregion to an electroluminescent medium. Further, the hole transportcompound is oxidized to a cation, and thus it becomes easier to injectand transport holes from the mixed region to the electroluminescentmedium. Preferably, the oxidative dopant includes various Lewis acidsand acceptor compounds; and the reductive dopant includes alkali metals,alkali metal compounds, alkaline earth metals, rare-earth metals, andmixtures thereof. A reductive dopant layer may be employed as acharge-generating layer to prepare an organic electroluminescent devicehaving two or more light-emitting layers, which emits white light.

An organic electroluminescent material according to one embodiment ofthe present disclosure may be used as light-emitting materials for awhite organic light-emitting device.

The white organic light-emitting device has been suggested in variousstructures such as a parallel side-by-side arrangement method, astacking arrangement method, or CCM (color conversion material) method,etc., according to the arrangement of R (Red), G (Green), B (blue), orYG (yellowish green) light-emitting units. In addition, the organicelectroluminescent material according to one embodiment of the presentdisclosure may also be applied to the organic electroluminescent devicecomprising a QD (quantum dot).

In order to form each layer of the organic electroluminescent device ofthe present disclosure, dry film-forming methods such as vacuumevaporation, sputtering, plasma, ion plating, etc., or wet film-formingmethods such as ink jet printing, spin coating, dip coating, flowcoating, etc., can be used.

When using a wet film-forming method, a thin film can be formed bydissolving or diffusing the materials forming each layer into anysuitable solvent such as ethanol, chloroform, tetrahydrofuran, dioxane,etc. The solvent is not specifically limited as long as the materialforming each layer is soluble or dispersible in the solvents, which donot cause any problems in forming a film.

It is possible to produce a display system, e.g., a display system forsmartphones, tablets, notebooks, PCs, TVs, or cars, or a lightingsystem, e.g., an outdoor or indoor lighting system, by using the organicelectroluminescent device of the present disclosure.

Hereinafter, the preparation method of the compound of the presentdisclosure, and the properties thereof, and the luminous property of theorganic electroluminescent device comprising the same will be explainedin detail with reference to the representative compounds of the presentdisclosure. However, the present disclosure is not limited to thefollowing examples.

Example 1: Preparation of Compound C-1

3.5 g of compound 1 (8.3 mmol) and 100 mL of benzene-D6 were introducedinto a flask and heated to dissolve all of compound 1. After cooling themixture to room temperature, 4.4 mL of triflic acid (49.8 mmol) wasadded thereto. After stirring the mixture at room temperature for 2hours and 30 minutes, 20 mL of heavy water were added thereto. Afterstirring for 10 minutes, the mixture was neutralized with K₃PO₄ aqueoussolution. An organic layer was extracted with dichloromethane, and theremaining moisture was removed using magnesium sulfate. The obtainedorganic layer was distilled under reduced pressure and separated bycolumn chromatography to obtain 1.5 g of compound C-1 (yield: 41.3%).The number of deuteriums substituted was observed with molecular weightand NMR.

MW M.P. 437.61 279.2° C.

Device Example 1: Producing an OLED Comprising a Compound According tothe Present Disclosure

An OLED comprising an organic electroluminescent compound according tothe present disclosure was produced as follows: A transparent electrodeindium tin oxide (ITO) thin film (10 Ω/sq) on a glass substrate for anOLED (GEOMATEC CO., LTD., Japan) was subjected to an ultrasonic washingwith acetone, ethanol, and distilled water, sequentially, and then wasstored in isopropanol. The ITO substrate was mounted on a substrateholder of a vacuum vapor deposition apparatus. Compound HI-1 wasintroduced into a cell of the vacuum vapor deposition apparatus, and thepressure in the chamber of the apparatus was then controlled to 10⁻⁶torr. Thereafter, an electric current was applied to the cell toevaporate the above-introduced material, thereby forming a first holeinjection layer having a thickness of 60 nm on the ITO substrate. Next,compound HI-2 was introduced into another cell of the vacuum vapordeposition apparatus and was evaporated by applying an electric currentto the cell, thereby forming a second hole injection layer having athickness of 5 nm on the first hole injection layer. Compound HT-1 wasthen introduced into another cell of the vacuum vapor depositionapparatus and was evaporated by applying an electric current to thecell, thereby forming a first hole transport layer having a thickness of20 nm on the second hole injection layer. Compound HT-2 was thenintroduced into another cell of the vacuum vapor deposition apparatusand was evaporated by applying an electric current to the cell, therebyforming a second hole transport layer having a thickness of 5 nm on thefirst hole transport layer. After forming the hole injection layers andthe hole transport layers, a light-emitting layer was formed thereon asfollows: Compound C-1 was introduced into one cell of the vacuum vapordepositing apparatus as a host of the light-emitting layer, and compoundBD was introduced into another cell as a dopant. The two materials wereevaporated at different rates and the dopant was deposited in a dopingamount of 2 wt % based on the total amount of the host and dopant toform a light-emitting layer having a thickness of 20 nm on the secondhole transport layer. Next, compound ET-1 and compound EI-1 wereevaporated at a rate of 1:1 in two other cells to deposit an electrontransport layer having a thickness of 35 nm on the light-emitting layer.After depositing compound EI-1 as an electron injection layer having athickness of 2 nm on the electron transport layer, an Al cathode havinga thickness of 80 nm was deposited on the electron injection layer byanother vacuum vapor deposition apparatus. Thus, an OLED was produced.

As a result, the minimum time taken to be reduced from 100% to 95% ofthe luminance at 2,000 nit was 76 hours.

Comparative Example 1: Producing an OLED Comprising a ConventionalCompound

An OLED was produced in the same manner as in Device Example 1, exceptthat compound H-1 was used as the host material of the light-emittinglayer.

As a result, the minimum time taken to be reduced from 100% to 95% ofthe luminance at 2,000 nit was 11 hours.

Comparative Example 2: Producing an OLED Comprising a ConventionalCompound

An OLED was produced in the same manner as in Device Example 1, exceptthat compound H-2 was used as the host material of the light-emittinglayer.

As a result, the minimum time taken to be reduced from 100% to 95% ofthe luminance at 2,000 nit was 25 hours.

Comparative Example 3: Producing an OLED Comprising a ConventionalCompound

An OLED was produced in the same manner as in Device Example 1, exceptthat compound H-3 was used as the host material of the light-emittinglayer.

As a result, the minimum time taken to be reduced from 100% to 95% ofthe luminance at 2,000 nit was 13 hours.

In the present disclosure, by producing an organic electroluminescentdevice by substituting hydrogens of the host compound of thelight-emitting layer with deuterium, it can be seen that the lifespancharacteristic is far superior to the organic electroluminescent deviceusing conventional compounds as a host. It is understood that suchimprovement in lifespan characteristic of an OLED is due to animprovement of stability of the material due to decrease of the zeropoint vibration energy of the deuterated compound, compared to acompound which is non-deuterated or deuterated with less deuterium. Inaddition, without intending to be limited by theory, in order to improvethe lifespan of the blue light-emitting fluorescent organicelectroluminescent device, the electron mobility needs to be controlled,and since dibenzofuran has faster hole mobility than aryls, a similareffect to a decrease of the electron mobility can be obtained. Withoutintending to be limited by theory, a decrease in electron mobility canlead to a decrease of degradation of adjacent layers, thereby increasinglifespan. In the aspect of such effect, deuterating a compound whereinan anthracene is substituted with dibenzofuran may be advantageouscompared to deuterating a compound wherein an anthracene is substitutedwith an aryl.

1. An organic electroluminescent compound represented by the followingformula 1:

wherein R₁ to R₈ each independently represent hydrogen, deuterium, ahalogen, a cyano, a substituted or unsubstituted (C1-C30)alkyl, asubstituted or unsubstituted (C6-C30)aryl, or a substituted orunsubstituted (5- to 30-membered)heteroaryl, with a proviso that one ofR₂ to R₄ is bonded to R

R₉ to R₁₆ each independently represent hydrogen or deuterium; Ar₁represents a substituted or unsubstituted (C6-C30)aryl, or a substitutedor unsubstituted (5- to 30-membered)heteroaryl; D_(N) means that Nhydrogen atoms are substituted with deuterium; and N represents aninteger of 8 to
 50. 2. The organic electroluminescent compound accordingto claim 1, wherein formula 1 is represented by any one of the followingformulas 1-1 to 1-3:

wherein R₁ to R₈, R₉ to R₁₈, Ar₁, and D_(N) are as defined in claim 1;and N represents an integer of 8 to
 30. 3. The organicelectroluminescent compound according to claim 1, wherein thesubstituents of the substituted alkyl, the substituted aryl, and thesubstituted heteroaryl in R₁ to R₈, and Ar₁ each independently are atleast one selected from the group consisting of deuterium; a halogen; acyano; a carboxyl; a nitro; a hydroxyl; a (C1-C30)alkyl; ahalo(C1-C30)alkyl; a (C2-C30)alkenyl; a (C2-C30)alkynyl; a(C1-C30)alkoxy; a (C1-C30)alkythio; a (C3-C30)cycloalkyl; a(C3-C30)cycloalkenyl; a (3- to 7-membered)heterocycloalkyl; a(C6-C30)aryloxy; a (C6-C30)arylthio; a (3- to 30-membered)heteroarylunsubstituted or substituted with a (C6-C30)aryl(s); a (C6-C30)arylunsubstituted or substituted with at least one of a (C1-C30)alkyl(s) anda (3- to 30-membered)heteroaryl(s); a tri(C1-C30)alkylsilyl; atri(C6-C30)arylsilyl; a di(C1-C30)alkyl(C6-C30)arylsilyl; a(C1-C30)alkyldi(C6-C30)arylsilyl; an amino; a mono- ordi-(C1-C30)alkylamino; a mono- or di-(C6-C30)arylamino; a(C1-C30)alkyl(C6-C30)arylamino; a (C1-C30)alkylcarbonyl; a(C1-C30)alkoxycarbonyl; a (C6-C30)arylcarbonyl; a di(C6-C30)arylboronyl;a di(C1-C30)alkylboronyl; a (C1-C30)alkyl(C6-C30)arylboronyl; a(C6-C30)aryl(C1-C30)alkyl; and a (C1-C30)alkyl(C6-C30)aryl.
 4. Theorganic electroluminescent compound according to claim 1, wherein R₁ toR₈ which are not bonded to

each independently represent hydrogen or deuterium; and Ar₁ represents asubstituted or unsubstituted (C6-C25)aryl, or a substituted orunsubstituted (5- to 20-membered)heteroaryl.
 5. The organicelectroluminescent compound according to claim 1, wherein R₁ to R₈ whichare not bonded to

each independently represent hydrogen or deuterium; and Ar₁ represents a(C6-C25)aryl unsubstituted or substituted with at least one of a(C1-C6)alkyl(s), a (C6-C15)aryl(s), and a (5- to15-membered)heteroaryl(s); or a (5- to 20-membered)heteroarylunsubstituted or substituted with a (C6-C12)aryl(s).
 6. The organicelectroluminescent compound according to claim 1, wherein N representsan integer of 13 to
 30. 7. The organic electroluminescent compoundaccording to claim 1, wherein the compound represented by formula 1 isselected from the group consisting of the following compounds:


8. An organic electroluminescent material comprising the organicelectroluminescent compound according to claim
 1. 9. An organicelectroluminescent device comprising the organic electroluminescentcompound according to claim
 1. 10. The organic electroluminescent deviceaccording to claim 9, wherein the organic electroluminescent compound iscomprised in a light-emitting layer.